Headbox for a machine for producing a fibrous web

ABSTRACT

A headbox for a machine for producing a fibrous web, in particular a paper, cardboard or tissue web from at least one fibrous stock suspension, includes a feeding device for feeding the at least one fibrous stock suspension; a perforated distribution pipe plate which is arranged immediately downstream from the feeding device in the flow direction of the at least one fibrous stock suspension and which includes a plurality of flow channels arranged in rows and columns; an intermediate channel which is arranged immediately downstream from the perforated distribution pipe plate in the flow direction of the at least one fibrous stock suspension and which extends in a width direction of the headbox and includes two walls, for example having the width of the machine; a turbulence generator which is arranged immediately downstream of the intermediate channel in the flow direction of the at least one fibrous stock suspension and which has a plurality of flow channels arranged in rows and columns; and a headbox nozzle which is arranged immediately downstream of turbulence generator in the flow direction of the at least one fibrous stock suspension and which has a nozzle gap. Feeding device, perforated distribution pipe plate and intermediate channel are arranged in a first alignment plane, and turbulence generator and headbox nozzle are arranged in a second alignment plane. The two alignment planes form an angle in the range of &gt;90 and &lt;180°, for example ≧100 and ≦170°, or ≧110 and ≦160°.

CROSS REFERENCE TO RELATED APPLICATIONS

This is a continuation of PCT application No. PCT/EP2010/056135, entitled “HEADBOX FOR A MACHINE FOR PRODUCING A FIBROUS WEB”, filed May 6, 2010, which is incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a headbox for a machine for producing a fibrous web, a paper, cardboard or tissue web from at least one fibrous stock suspension, including a feeding device for feeding the at least one fibrous stock suspension; a perforated distribution pipe plate which is arranged immediately downstream from the feeding device in a flow direction of the at least one fibrous stock suspension and which includes a plurality of flow channels arranged in rows and columns; an intermediate channel which is arranged immediately downstream from the perforated distribution pipe plate in the flow direction of the at least one fibrous stock suspension and which extends in a width direction of the headbox and includes two walls, for example having the width of the machine; a turbulence generator which is arranged immediately downstream of the intermediate channel in the flow direction of the at least one fibrous stock suspension and which has a plurality of flow channels arranged in rows and columns; and a headbox nozzle which is arranged immediately downstream of the turbulence generator in the flow direction of the at least one fibrous stock suspension and which has a nozzle gap. The feeding device, the perforated distribution pipe plate and the intermediate channel are arranged in a first alignment plane, and the turbulence generator and the headbox nozzle are arranged in a second alignment plane. The two alignment planes form an angle in the range of approximately >90 and <180°, for example ≧100 and ≦170°, or ≧110 and ≦160°.

2. Description of the Related Art

A headbox of this type has been known in expert circles already for several years and is built and distributed for example by Voith Paper under the “W-Headbox” label. It is preferably used in paper or cardboard machines having a so-called Fourdrinier wire forming unit.

It is known that more recent developments on the headbox in machines for producing a fibrous web have resulted in that, in addition to the actual fibrous stock suspension which is required to produce the fibrous web an additional controlled addition of a fluid, for example water or fibrous suspension having a different stock consistency which is known in expert circles as “dilution water”, occurs. This addition occurs at several locations which are distributed across the width of the headbox. The volume and/or the characteristic of the dilution water are hereby adjustable. Through this measure the basis weight cross profile can for example be efficiently controlled, and/or occurrence of cross-flows in the headbox effectively prevented.

A headbox of this type with the described dilution water technology is known for example from document DE 41 19 593 C2 (“ModuleJet”). The preferably controlled metered addition of the dilution water in partial streams into the at least one fibrous stock suspension occurs hereby through inlet openings in the wall of the mixing chamber or directly into the turbulence generator. In order to limit the effect of the added dilution water locally, separation walls are provided in some instances in the mixing chamber.

A headbox of this type with the described dilution water technology may also be equipped with an alternative dilution water system, for example “Jetco”, “Annular Gap Metering” or “Injection System”. All known dilution water systems by well-known manufacturers of machinery for the production of a fibrous web are systems which can only more or less effectively, or in other words only partially fulfill the demands for effective blending of fibrous stock suspension and dilution water, sufficient volume flow consistency, a small effective width and a small mapping offset.

Nonetheless, local addition of dilution water into the headboxes has proven especially advantageous in many applications. In such instances it is desirable to retrofit already existing and otherwise still usable headboxes to this new dilution water technology described at the beginning. For this purpose previously large and also heavy components of the headbox must be removed and, accepting a high risk during transport, must be brought to the supplier since, as a rule, the necessary rework and adaptions can only be carried out there. Due to these missing parts the headbox is not usable during this period. Moreover, retrofitting the removed headbox is very expensive and possibly also associated with technological risks.

What is needed in the art is an improved headbox so that a technically simple and reliable dilution water system may be realized. Moreover, it should be cost-effective and represent a more favorable retrofit solution with less downtime.

SUMMARY OF THE INVENTION

The present invention provides a headbox having on at least on one wall—which is for example the width of the machine—of the intermediate channel a plurality of metering devices which are spaced apart from each other in a width direction as well as in a longitudinal direction of the headbox. The plurality of metering devices are arranged for example for controlled metered addition of a fluid in partial fluid streams into the at least one fibrous stock suspension. The individual metering devices for the controlled, metered addition of the fluid in at least one partial fluid stream into the at least one fibrous stock suspension includes a metering channel having a metering channel opening and a metering channel center line. The respective metering channel opening of the metering channel of the individual metering device for controlled metered addition of the fluid in at least one partial fluid stream into the at least one fibrous stock suspension is aligned such that the metering channel center line of the metering channel impinges on the turbulence generator when forming an impingement point. The turbulence generator is hereby preferably a turbulence generator known to the expert.

The headbox according to the present invention allows realization of a technically simple and reliable dilution water system. Even with possibly locally greatly differing dilution water or respectively fluid volumes, a good volume flow consistency is achieved across the entire machine width and, due to the addition of the dilution water or respectively the fluid into the direct catchment area of the turbulence generator a narrow and sharply defined effective response in the fibrous web is produced. “Straying” of the partial stream of dilution water or respectively fluid can occur only to a very limited extent. Due to the targeted, locally stable and, for example controlled, metered addition of the dilution water or respectively the fluid and the intensive blending in the flow channels of the turbulence generator downstream from the metering zone, with separate guidance of the blended streams to the beginning of the headbox nozzle, the demands upon an optimum dilution water system are extensively, even completely met.

The headbox according to the present invention is also a more suitable retrofit solution with less downtime, compared with the already known retrofit solutions. Basically only at least one wall of the intermediate channel must be equipped with the metering devices for controlled metered addition of the dilution water or respectively the fluid in partial streams into the at least one fibrous stock suspension. The remaining components and component groups of the previous headbox can remain and can continue to be used without any changes. The headbox according to the present invention can be implemented easily and without problems locally on-site of the existing machine for the production of a fibrous web.

In a first embodiment of the headbox according to the present invention, the respective metering channel opening of the metering channel of the individual metering devices for controlled metered addition of the fluid in at least one partial fluid stream into the at least one fibrous material suspension is aligned such that the metering channel center line of the metering channel impinges for example approximately centered, or centered between the columns of two adjacent flow channels onto the turbulence generator when forming an impingement point. A division of the added partial fluid stream occurs. Since the added partial fluid stream does not flow directly into at least one flow channel of the turbulence generator very stable conditions in regard to the volume flow consistency are achieved. Moreover, water jet pumping effects and similar phenomena are extensively avoided and lead to only insignificant influences, even at changing volumes of the partial fluid streams.

An additional embodiment of the headbox according to the present invention provides that the flow channels of the turbulence generator which are arranged in one row, feature a row separation of the flow channels and that the metering channel center lines of the metering channels of the metering devices for controlled metered addition of the fluid in partial fluid streams into the at least one fibrous stock suspension located at a distance from each other in the width direction of the headbox which are allocated to the flow channels of the turbulence generator located in this row feature a row separation of the metering channel center lines, whereby the row separation of the metering channel center lines assumes the same or double the value of the row separation as the flow channels. If however, the two row separations assume the same value then precisely one row of metering channels is allocated to each row of flow channels. If in contrast, the row separation of metering channel center lines assumes double the value of the row separation of the flow channels, then one row of metering channels is allocated only to every second row of flow channels. The row separation of the flow channels may for example assume a value of 25, 33, 50, 66 or 100 millimeters (mm).

Furthermore, a third embodiment of the headbox according to the present invention provides that the respective metering channel opening of the metering channel of the individual metering devices for the controlled metered addition of the fluid in at least one partial fluid stream into the at least one fibrous stock suspension is aligned such that the metering channel center line of the metering channel may impinge outside or inside the row of the adjacent flow channels onto the turbulence generator when forming an impingement point. The impingement outside the metering channel center line can hereby assume a value of up to 50% of the column separation of the flow channels. The effective impingement surface can thereby be effectively enlarged so that again, very stable conditions are achieved in regard to volume flow consistency.

The metering channel center line of the metering channel may of course also impinge on the turbulence generator inside the row of the adjacent flow channels when forming an impingement point. In this possible layout, the impingement point of the metering channel center line of the metering channel of the metering device then aligns with the two adjacent flow channels of the turbulence generator.

Moreover, the flow channels of the turbulence generator arranged in one column feature a column separation of the flow channels and the metering channel center lines of the metering channels of the metering devices for controlled, metered addition of the fluid in partial fluid streams into the at least one fibrous stock suspension joining at different heights which are allocated to the flow channels of the turbulence generator which are located in the column feature a column separation of the metering channel center lines, whereby the column separation of the metering channel center lines can assume the same, or double the value of the column separation of the flow channels. If now, the two column separations assume the same value, then precisely one column of metering channels is allocated to each column of flow channels. If in contrast, the column separation of metering channel center lines assumes double the value of the column separation of the flow channels, then one column of metering channels is allocated only to every second column of flow channels.

The respective metering channel opening of the metering channel of the individual metering devices for controlled metered addition of the fluid in at least one partial fluid stream into the at least one fibrous stock suspension can of course also be aligned such, that the metering channel center line of said metering channel impinges centered or approximately centered, or if required also slightly offset on a flow channel of the turbulence generator when forming an impingement point.

Moreover, the flow channels of the turbulence generator located in two adjacent rows can be arranged offset relative to each other, for example center-offset. The distance between the flow channels of the turbulence generator located in adjacent rows is hereby considerably increased. This in turn leads to an advantageous enlargement of the effective impingement surface, so that again, very stable conditions are achieved in regard to the volume flow consistency.

The flow channels of the turbulence generator located in two adjacent rows can of course also be arranged without offset relative to each other. A rectangular arrangement grid is hereby created for the flow channels of the turbulence generator.

In another embodiment the metering channels of the metering devices located in one column for, for example, controlled metered addition of the fluid in partial fluid streams into the at least one fibrous stock suspension are connected with a common supply channel. Thereby a technically elegant, cost-effective layout is achieved which is fluidic and technologically not disadvantageous.

In an alternative embodiment each metering channel of the individual metering devices for controlled metered addition of the fluid in partial fluid streams into the at least one fibrous stock suspension is connected with its own supply channel. This technically expensive design provides the advantage of greater arrangement possibilities, in particular also during the operation of the machine for the production of a fibrous web.

The respective metering channel opening of the individual metering channel of the metering devices for controlled metered addition of the fluid in at least one partial fluid stream into the at least one fibrous stock suspension is located at a vertical and uniform or approximately uniform distance in the range of approximately 1 to 50 mm, for example 3 to 30 mm, or 10 to 30 mm from the turbulence generator. This provides the advantage of a space saving arrangement at fluidic and technologically optimum operating conditions of the machine for the production of a fibrous web.

Moreover, the respective metering channel of the metering devices for controlled metered addition of the fluid in at least one partial fluid stream into the at least one fibrous stock suspension can have at least in part a constant or an intermittently enlarging cross sectional inside surface. An improvement of distribution in the z-direction can hereby be brought about.

The respective metering devices for controlled metered addition of the fluid in at least one partial fluid stream into the at least one fibrous stock suspension may include a metering pipe. This embodiment of the metering device possesses optimum fluidic properties and is in addition especially suitable in regard to production-technical aspects. The metering pipe may hereby assume any known pipe cross section, namely round, approximately round, oval, triangular, rectangular, square, etc.

Moreover, the respective metering channel of the metering pipe can have a rotationally symmetrical cross sectional inside surface along its metering channel center line, and the individual metering pipe can have a rotationally symmetrical outside surface with a diameter in the range of approximately 3 to 25 mm, for example 4 to 16 mm, or 5 to 10 mm. The fluidic properties of the metering devices can herewith be improved further.

The fluid consists, for example, of water, such as clarified water or a fibrous stock suspension, in particular white water, whose concentration is different than the average concentration of the at least one fibrous stock suspension flowing through the headbox. These types of fluids have already proven themselves well in similar applications.

The inventive headbox is extremely well suited for utilization in a machine for the production of a fibrous material web, especially a paper or cardboard web. The fibrous material web produced in the machine with at least one inventive headbox possesses outstanding properties throughout, since among other advantages, control of its fiber orientation cross profile as well as its base weight cross profile is possible.

BRIEF DESCRIPTION OF THE DRAWINGS

The above-mentioned and other features and advantages of this invention, and the manner of attaining them, will become more apparent and the invention will be better understood by reference to the following description of embodiments of the invention taken in conjunction with the accompanying drawings, wherein:

FIG. 1 is a vertical and schematic longitudinal sectional view of one design form of a headbox for a machine to produce a fibrous web in accordance with the current state of the art;

FIG. 2 is a partial schematic sectional view of a first embodiment of an inventive headbox for a machine to produce a fibrous web;

FIG. 3 is a partial and schematic sectional view of a second embodiment of an inventive headbox for a machine to produce a fibrous stock suspension;

FIG. 4 is an illustration of a first metered addition arrangement in an inventive headbox for a machine to produce a fibrous web; and

FIG. 5 is an illustration of a second metered addition arrangement in an inventive headbox for a machine to produce a fibrous web.

Corresponding reference characters indicate corresponding parts throughout the several views. The exemplifications set out herein illustrates embodiments of the invention and such exemplifications are not to be construed as limiting the scope of the invention in any manner.

DETAILED DESCRIPTION OF THE INVENTION

Referring now to the drawings, and more particularly to FIG. 1, there is shown a vertical and schematic longitudinal view of an exemplary design form of headbox 1 for a machine to produce fibrous web 3 from fibrous stock suspension 2. Illustrated headbox 1 may of course also be designed as a multi-layer headbox which utilizes at least two different fibrous stock suspensions to produce fibrous web 3. Fibrous web 3 can hereby be a paper, cardboard or tissue web.

Headbox 1 includes one feed device 4, for example in the embodiment of illustrated cross distribution pipe 5 or a circular distributor having a plurality of tubes and which is not illustrated, feeding one fibrous stock suspension 2.

Viewed in flow direction R (arrow) of fibrous stock suspension 2, for example three-row perforated distribution pipe plate 6 is located immediately downstream from feed device 4 and which is equipped with a plurality of flow channels 7 which are arranged in three rows Z and several columns S. In a different, not illustrated embodiment, the number or rows Z can of course also be less than or greater than three.

Again, in flow direction R (arrow) of fibrous stock suspension 2 intermediate channel 8 extending in width direction B (arrow) of headbox 1 and preferably two machine-wide walls 9.1, 9.2 is located immediately downstream.

In flow direction R (arrow) of fibrous stock suspension 2, for example three-row, turbulence generator 10 having a plurality of flow channels 11 arranged in three rows Z and in several columns S is located immediately downstream from intermediate channel 8 (compare FIGS. 4 and 5). The number of rows Z can of course be less than or greater than three.

During operation of headbox 1, fibrous stock suspension 2 is divided into partial fibrous stock suspension streams in turbulence generator 10 and, after emerging from turbulence generator 10 is brought together again in machine-wide chamber 12 in the embodiment of headbox nozzle 13 including nozzle gap 14 in order to enable formation of machine-wide fibrous web 3. As already known, flow channels 6 of turbulence generator 10 are in the embodiment of, for example, thin-walled turbulence pipes and/or turbulence pipe inserts with at least partially constant, at least partially divergent, at least partially convergent and/or intermittent cross sectional surfaces.

If necessary, headbox nozzle 13 may be equipped on its outlet side with at least one baffle 15 which is indicated by dashed lines.

A separating element which is well known to the expert and which is not explicitly illustrated, such as a lamella, may also be provided in headbox nozzle 13. If a multitude of separating elements, especially lamellas are provided in headbox nozzle 13, they can have different lengths and possibly also different properties, such as surface profiles, etc.

Moreover, feeding device 4, perforated distribution plate 6 and intermediate channel 8 are arranged in first alignment plane AE.1, and turbulence generator 10 and headbox nozzle 13 are arranged in second alignment plane AE.2. The two alignment planes AE.1, AE.2 form obtuse angle α in the range of approximately >90 and <180°, for example ≧100 and ≦170°, or ≧110 and ≦160°. Headbox 1 therefore exhibits considerable redirection 16.

Referring now to FIG. 2, there is shown a partial schematic sectional view of a first embodiment of headbox 1 according to the present invention for a machine to produce a fibrous web from fibrous suspension 2 (arrow). The illustrated segment is indicated in FIG. 1 in a circle K with dashed lines.

The basic construction of this partially and schematically illustrated headbox 1 is substantially consistent with the basic construction of headbox 1 schematically depicted in FIG. 1. We therefore refer to the description provided for that drawing. It can be clearly seen that intermediate channel 8 is arranged in first alignment plane AE.1 and turbulence generator 10 is arranged in second alignment plane AE.2. The two alignment planes AE.1, AE.2 form obtuse angle α in the range of approximately >90 and <180°, for example ≧100 and ≦170°, or ≧110 and ≦160°. Headbox 1 therefore exhibits considerable redirection 16.

On the upper and, for example, machine-wide wall 9.2 of intermediate channel 8 a plurality of metering devices 17 which are spaced apart from each other in width direction B (arrow) as well as longitudinal direction L (arrow) of headbox 1 are arranged for example for the controlled metered addition of fluid 18 (arrow) in partial fluid streams 18.T (arrows) into fibrous stock suspension 2 (arrow). Due to the addition of fluid 18 (arrow) in partial fluid streams 18.T (arrow) into fibrous stock suspension 2 (arrow) blended partial streams 2.1 (arrow) result which are then combined to a common blended stream in the headbox nozzle. The metering devices for controlled metered addition of fluid 18 in partial fluid stream 18.T (arrow), for example valves, are well known by the expert and are therefore not explicitly illustrated.

Individual metering devices 17 for controlled, metered addition of fluid 18 (arrow) in at least one partial fluid stream 18.T (arrow) into at least one fibrous stock suspension 2 includes metering channel 19 including metering channel opening 19.1 and metering channel center line 19.M. Respective metering devices 17 for controlled, metered addition of fluid 18 in at least one partial fluid stream 18.T (arrow) into at least one fibrous stock suspension 2 includes one metering pipe 17.1.

Respective metering channel 19 of metering pipe 17.1 has rotationally symmetrical cross sectional inside surface 19.1 along metering channel center line 19.M. Individual metering pipe 17.1 furthermore may have a rotationally symmetrical outside surface 19.A with diameter 19.D in the range of approximately 3 to 25 mm, for example 4 to 16 mm, or 5 to 10 mm.

Individual supply channel 19 of metering devices 17 moreover includes at least in parts a constant or a intermittently enlarging cross sectional surface inside 19.1.

Individual metering channel opening 19.1 of metering channel 19 of individual metering device 17 for controlled metered addition of fluid 18 in at least one partial fluid stream 18.T (arrow) into at least one fibrous stock suspension 2 is aligned such that metering channel center line 19.M of metering channel 19 impinges on turbulence generator 10 when forming impingement point AP (cross).

Moreover, metering channels 19 of metering devices 17 for controlled metered addition of fluid 18 (arrow) in partial fluid streams 18.T (arrow) into fibrous stock suspension 2 which are arranged in one column S are connected with common supply channel 20. Supply channel 20 in turn is connected with a supply system for fluid 18 which is not illustrated, whereby a device which is known to the expert and which therefore is not explicitly illustrated, for example a valve for controlled metered addition of fluid 18 (arrow) may be provided in supply channel 20 and/or in the supply system.

Obviously, every metering channel of the individual metering devices for controlled metered addition of the fluid in partial fluid streams into the fibrous stock suspension can also be connected in a non-illustrated manner with its own supply channel.

Moreover, respective metering channel opening 19.1 of metering channel 19 of metering devices 17 for controlled metered addition of fluid 18 in at least one partial fluid stream 18.T (arrow) into fibrous stock suspension 2 is located at vertical and uniform or approximately uniform distance A in the range of approximately 1 to 50 mm, for example 3 to 30 mm, or 10 to 30 mm from turbulence generator 10. Metering channel opening 19.1 of respective metering channel 19 of individual metering device 17 is also arranged parallel or approximately parallel to infeed side 10.E of turbulence generator 10. Obviously it can also be arranged in a non-illustrated manner at an angle to the infeed side of the turbulence generator.

Referring now to FIG. 3, there is shown a partial and schematic sectional view of a second embodiment of headbox 1 according to the present invention for a machine to produce a fibrous web from fibrous stock suspension 2 (arrow). The illustrated segment is indicated in FIG. 1 in circle K with dashed lines. The basic construction of this partially and schematically illustrated headbox 1 is substantially consistent with the basic construction of headbox 1 schematically depicted in FIG. 1. We therefore refer to the description provided for that drawing.

It can be clearly seen that intermediate channel 8 is arranged in first alignment plane AE.1 and turbulence generator 10 is arranged in second alignment plane AE.2. The two alignment planes AE.1, AE.2 form obtuse angle α in the range of approximately >90 and <180°, for example ≧100 and ≦170°, or ≧110 and ≦160°. Headbox 1 therefore exhibits considerable redirection 16.

On the upper and, for example machine-wide, wall 9.2 of intermediate channel 8 a plurality of metering devices 17 which are spaced apart from each other in width direction B (arrow) as well as in longitudinal direction L (arrow) of headbox 1 are arranged for example for controlled metered addition of fluid 18 (arrow) in partial fluid streams 18.T (arrow) into fibrous stock suspension 2 (arrow). Due to the addition of fluid 18 (arrow) in partial fluid streams 18.T (arrow) into fibrous stock suspension 2 (arrow) blended partial streams 2.1 (arrow) result which are then combined to a common blended stream in the headbox nozzle. The metering devices for controlled metered addition of fluid 18 in partial fluid stream 18.T (arrow), for example valves, are well known by the expert and are therefore not explicitly illustrated.

Individual metering devices 17 for controlled, metered addition of fluid 18 in at least one partial fluid stream 18.T (arrow) into at least one fibrous stock suspension 2 includes metering channel 19 including metering channel opening 19.1 and metering channel center line 19.M. Respective metering device 17 for controlled, metered addition of fluid 18 in at least one partial fluid stream 18.T (arrow) into at least one fibrous stock suspension 2 includes one metering pipe 17.1.

Respective metering channel 19 of metering pipe 17.1 has rotationally symmetrical cross sectional inside surface 19.1 along metering channel center line 19.M. Individual metering pipe 17.1 furthermore may have rotationally symmetrical outside surface 19.A with diameter 19.D in the range of approximately 3 to 25 mm, for example 4 to 16 mm, or 5 to 10 mm.

Individual supply channel 19 of metering device 17 moreover includes at least in parts a constant or an intermittently enlarging cross sectional surface inside 19.1.

Individual metering channel opening 19.1 of metering channel 19 of individual metering device 17 for controlled metered addition of fluid 18 in at least one partial fluid stream 18.T (arrow) into at least one fibrous stock suspension 2 is aligned such that metering channel center line 19.M of metering channel 19 impinges on turbulence generator 10 when forming impingement point AP (cross).

Moreover, metering channels 19 of metering devices 17 which are arranged in one column S for controlled metered addition of fluid 18 in partial fluid streams 18.T (arrow) into at least one fibrous stock suspension 2 are connected with common supply channel 20. Supply channel 20 in turn is connected with a supply system for fluid 18 which is not illustrated, whereby a device which is known to the expert and which therefore is not explicitly illustrated, for example a valve for controlled metered addition of fluid 18 (arrow) may be provided in supply channel 20 and/or in the supply system.

Obviously, every metering channel of the individual metering devices for controlled metered addition of the fluid in partial fluid streams into the at least one fibrous stock suspension can also be connected in a non-illustrated manner with its own supply channel.

Moreover, respective metering channel opening 19.1 of metering channel 19 of metering device 17 for controlled metered addition of fluid 18 in at least one partial fluid stream 18.T (arrow) into fibrous stock suspension 2 is located at a vertical and uniform or approximately uniform distance A in the range of approximately 1 to 50 mm, for example 3 to 30 mm, or 10 to 30 mm from turbulence generator 10. The metering channel opening of respective metering channel 19 of individual metering device 17 is also arranged parallel or approximately parallel to inside 9.2.1 of upper and, for example machine-wide, wall 9.2 of intermediate channel 8. Obviously it can also be arranged in a non-illustrated manner at an angle to the infeed side of the turbulence generator.

Referring now to FIGS. 4 and 5, there are shown two metering arrangements of inventive headbox 1 according to the present invention for a machine to produce a fibrous web. In the example, flow channels 11 of turbulence generator 10 are arranged in three rows Z.1 through Z.3 (Z) and in four meandering columns S.1 through S.4 (S).

In both arrangements, flow channels 11 of turbulence generator 10 which are arranged in two adjacent rows Z.1, Z.2 and Z.3 are arranged offset relative to each other. In the two present illustrations they are center-offset relative to each other, so that flow channels 11 of lower row Z.1 and flow channels 11 of upper row Z.3 feature the same layout in width direction B (double arrow) of headbox 1.

The flow channels of the turbulence generator located in two adjacent rows can of course also be arranged without offset relative to each other. A rectangular arrangement grid is hereby created for the flow channels of the turbulence generator.

Moreover, metering channel openings 19.1 of metering channels 19 of metering devices 17 in the embodiment of metering pipe 17.1 which is indicated by dashed lines, for controlled metered addition of the fluid in partial fluid streams into the at least one fibrous stock suspension are illustrated.

Individual metering channel opening 19.1 of metering channel 19 of metering device 17 is thereby aligned such that metering channel center line 19.M of each metering channel 19 of metering devices 17 impinges approximately in the center, or in the center between columns S.2 and S.3 of two adjacent flow channels 11 onto turbulence generator 10 when forming impingement point AP.

Moreover, flow channels 11 of turbulence generator 10 arranged in one row Z.1, Z.2 and Z.3 feature a row separation of flow channels TZ.11. The row separation of the flow channels can assume a value for example of approximately 25, 33, 50, 66 or 100 mm. Metering channel center lines 19.M of metering channels 19 of metering devices 17 located at a distance from each other in width direction B (arrow) of headbox 1 which are allocated to flow channels 11 of turbulence generator 10 which are arranged in this row Z.1, Z.2 and Z.3 feature a row separation of metering channel center lines TZ.19.M. In the two present illustrations, the row separation of metering channel center lines TZ.19.M assumes double the value of the row separation of flow channels TZ.11. Obviously the two row separations TZ.19.M and TZ.11 can also assume the same value.

Moreover, flow channels 11 of turbulence generator 10 which are arranged in one column S.2 and S.3 feature column separation TS.11. Metering channel center lines 19.M of metering channels 19 of metering devices 17 which join at different heights and which are allocated to flow channels 11 of turbulence generator 10 arranged in this column S.2 and S.3 feature a column separation of metering channel center lines TS.19.M.

In the illustration in FIG. 4, that is in the first arrangement the column separation of metering channel center lines TS.19.M assumes the same value as the column separation of flow channels TS.11. Therefore, one row of metering channels 19 of metering devices 17 respectively are allocated to all rows Z.1, Z.2 and Z.3 of flow channels 11 of turbulence generator 10. The entire volume of fibrous stock suspension is herewith supplied with the fluid in partial fluid streams.

In the illustration in FIG. 5, that is the second arrangement, the column separation of metering channel center lines TS.19.M assumes double the value of the column separation of flow channels TS.11. Therefore, respectively one row of metering channels 19 of metering devices 17 are allocated only to rows Z.1 and Z.3 of flow channels 11 of turbulence generator 10. Therefore, only ⅔ of the volume of fibrous stock suspension is supplied with the fluid in partial fluid streams.

Also, individual metering channel opening 19.1 of metering channel 19 of metering device 17 in FIGS. 4 and 5 is aligned such that metering channel center line 19.M of metering channel 19 impinges outside row Z.1, Z.2 and Z.3 (FIG. 4) or respectively Z.1 and Z.3 (FIG. 5) of adjacent flow channels 11 onto turbulence generator 10 when forming respective impingement point AP.

In a non-illustrated manner, the metering channel center line of the metering channel may of course also impinge on the turbulence generator inside the row of the adjacent flow channels when forming an impingement point.

Fluid 18 used in the embodiments illustrated in FIGS. 2, 3, 4 and 5 consists, for example, of water, such as white water or clarified water or of at least one fibrous stock suspension whose concentration is different than the average concentration of at least one fibrous stock suspension 2 (arrow) flowing through headbox 1.

Headbox 1 illustrated and described respectively in FIGS. 2, 3, 4 and 5, is suitable for utilization in a machine for the production of fibrous material web 3, such as a paper or cardboard web from at least one fibrous stock suspension 2 (arrow).

The properties of the embodiments of headbox 1 illustrated and described in FIGS. 2, 3, 4 and 5 can also be combined, at least in part in a manner known to the expert.

In summary it can be stated that the headbox according to the present invention provides a technically simple and reliable dilution water system. Moreover it permits a cost-effective design and provides a more favorable retrofit solution with less downtime.

While this invention has been described with respect to at least one embodiment, the present invention can be further modified within the spirit and scope of this disclosure. This application is therefore intended to cover any variations, uses, or adaptations of the invention using its general principles. Further, this application is intended to cover such departures from the present disclosure as come within known or customary practice in the art to which this invention pertains and which fall within the limits of the appended claims.

COMPONENT IDENTIFICATION LIST

-   1 Headbox -   2 Fibrous stock suspension (arrow) -   2.1 Blended stream (arrow) -   3 Fibrous web -   4 Feed device -   5 Cross distribution pipe -   6 Perforated distribution pipe plate -   7 Channel -   8 Intermediate channel -   9.1 Wall; lower wall -   9.2 Wall; upper wall -   9.2.I Inside -   10 Turbulence generator -   10.E Infeed side -   11 Flow channel -   12 Machine-wide chamber -   13 Headbox nozzle -   14 Nozzle gap -   15 Baffle -   16 Reorientation -   17 Metering devices for example for controlled metered addition of a     fluid in partial fluid streams -   17.1 Metering pipe -   18 Fluid -   18.T Partial fluid stream (arrow) -   19 Metering channel -   19.1 Metering channel opening -   19.2 Metering component -   19.A Outside surface -   19.D Diameter -   19.I Cross sectional inside surface -   19.M Metering channel center line -   20 Supply channel -   A Distance -   AE.1 First alignment plane -   AE.2 Second alignment plane -   AP Impingement point (cross) -   B Width direction (arrow; double arrow) -   K Circle -   L Longitudinal direction -   R Flow direction (arrow) -   S; S.1 Column -   S; S.2 Column -   S; S.3 Column -   S; S.4 Column -   TS.11 Column separation of flow channels -   TS.19.M Column separation of metering channel center lines -   TZ.11 Row separation of flow channels -   TZ.19.M Row separation of metering channel center lines -   Z; Z.1 Row; lower row -   Z; Z.2 Row; upper row -   Z; Z.3 Row; middle row -   α Angle 

1. A headbox for a machine for producing a fibrous material web from at least one fibrous stock suspension, the headbox comprising: a feeding device for feeding the at least one fibrous stock suspension; a perforated distribution pipe plate arranged immediately downstream from said feeding device in a flow direction of the at least one fibrous stock suspension includes a plurality of flow channels arranged in a plurality of rows and columns; an intermediate channel arranged immediately downstream from said perforated distribution pipe plate in said flow direction of the at least one fibrous stock suspension extends in a width direction of the headbox and includes two walls, said feeding device, said perforated distribution pipe plate and said intermediate channel being arranged in a first alignment plane and said intermediate channel including a plurality of metering devices for metered addition of a fluid in a plurality of partial fluid streams into the at least one fibrous stock suspension on at least one of said two walls and spaced apart from each other in said width direction and a longitudinal direction of the headbox, each individual of said plurality of metering devices including a metering channel having a metering channel opening and a metering channel center line, said metering channel opening being aligned such that said metering channel center line impinges on said turbulence generator to form an impingement point; a turbulence generator arranged immediately downstream of said intermediate channel in said flow direction of the at least one fibrous stock suspension has a plurality of flow channels arranged in a plurality of rows and columns; and a headbox nozzle arranged immediately downstream of said turbulence generator in said flow direction of the at least one fibrous stock suspension has a nozzle gap, said turbulence generator and said headbox nozzle being arranged in a second alignment plane, said first alignment plane and said second alignment plane forming an angle in a range of approximately between >90 and <180°.
 2. The headbox according to claim 1, wherein the headbox for producing the fibrous material web is for producing one of a paper, cardboard and a tissue web.
 3. The headbox according to claim 1, wherein said two walls of said intermediate channel and the machine for producing the fibrous material web have a width which is the same.
 4. The headbox according to claim 1, wherein said angle is in a range of approximately between ≧100 and ≦170°.
 5. The headbox according to claim 4, wherein said angle is in a range of approximately between ≧110 and ≦160°.
 6. The headbox according to claim 1, wherein said plurality of metering devices for addition of said fluid in said plurality of fluid streams into the at least one fibrous stock suspension are for controlled and metered addition of said fluid.
 7. The headbox according to claim 6, wherein said metering channel opening of said individual metering device is aligned such that said metering channel center line impinges approximately centered between said plurality of columns of two adjacent of said plurality of flow channels onto said turbulence generator to form said impingement point.
 8. The headbox according to claim 7, wherein said metering channel opening of said individual metering device is aligned such that said metering channel center line impinges centered between said plurality of columns of two adjacent of said plurality of flow channels onto said turbulence generator to form said impingement point.
 9. The headbox according to claim 7, wherein said flow channels of said turbulence generator arranged in one of said plurality of rows feature a row separation and said metering channel center lines of said metering channels which are allocated to said flow channels of said turbulence generator located in said one of said plurality of rows feature a row separation of said metering channel center lines, said row separation of said metering channel center line assuming one of the same and double a value of said row separation of said flow channels of said turbulence generator.
 10. The headbox according to claim 9, wherein said metering channel opening of said metering channel of said individual metering device is aligned such that said metering channel center line impinges one of outside and inside said row of adjacent flow channels of said turbulence generator when forming said impingement point onto said turbulence generator.
 11. The headbox according to claim 10, wherein said flow channels of said turbulence generator arranged in one column of said plurality of columns feature a column separation of said flow channels and said metering channel center lines of said metering channels of said metering devices join at different heights allocated to said flow channels of said turbulence generator located in said one column feature a column separation of said metering channel center lines, said column separation of said metering channel center lines assuming one of the same and double a value of said column separation of said flow channels of said turbulence generator.
 12. The headbox according to claim 1, wherein said flow channels of said turbulence generator located in two adjacent of said plurality of rows are arranged offset relative to each other.
 13. The headbox according to claim 12, wherein said flow channels of said turbulence generator located in said two adjacent of said plurality of rows are arranged center-offset relative to each other.
 14. The headbox according to claim 1, wherein all of said metering channels of said plurality of metering devices are connected with a common supply channel.
 15. The headbox according to claim 13, wherein each of said metering channels of said individual metering devices is connected with its own supply channel.
 16. The headbox according to claim 1, wherein said metering channel opening of said metering channel of each of said individual metering devices is located at a vertical and at least approximately uniform distance in a range of approximately between 1 to 50 mm from said turbulence generator.
 17. The headbox according to claim 16, wherein said distance is in a range of approximately between 10 to 30 mm from said turbulence generator.
 18. The headbox according to claim 17, wherein said distance is in a range of approximately between 3 to 30 mm from said turbulence generator.
 19. The headbox according to claim 1, wherein said metering channel of said individual metering devices features at least in part one of a constant and an intermittently enlarging cross sectional inside surface.
 20. The headbox according to claim 1, wherein said individual metering devices include a metering pipe.
 21. The headbox according to claim 20, wherein said metering channel of said individual metering devices has a rotationally symmetrical cross-sectional inside surface along its respective metering channel center line.
 22. The headbox according to claim 21, wherein said metering pipe of said individual metering devices has a rotationally symmetrical outside surface with a diameter in a range of approximately between 3 to 25 mm.
 23. The headbox according to claim 22, wherein said diameter is in a range of approximately between 4 to 16 mm.
 24. The headbox according to claim 23, wherein said diameter is in a range of approximately between 5 to 10 mm.
 25. The headbox according to claim 1, wherein said fluid consists of one of at least water and at least one fibrous stock suspension having a concentration different than an average concentration of the at least one fibrous stock suspension flowing through the headbox.
 26. The headbox according to claim 25, wherein said fluid consisting of said water is one of white water and clarified water.
 27. A machine for producing a fibrous material web, the machine comprising: a headbox comprising; a feeding device for feeding the at least one fibrous stock suspension; a perforated distribution pipe plate arranged immediately downstream from said feeding device in a flow direction of the at least one fibrous stock suspension includes a plurality of flow channels arranged in a plurality of rows and columns; an intermediate channel arranged immediately downstream from said perforated distribution pipe plate in said flow direction of the at least one fibrous stock suspension extends in a width direction of the headbox and includes two walls, said feeding device, said perforated distribution pipe plate and said intermediate channel being arranged in a first alignment plane and said intermediate channel including a plurality of metering devices for metered addition of a fluid in a plurality of partial fluid streams into the at least one fibrous stock suspension on at least one of said two walls and spaced apart from each other in said width direction and a longitudinal direction of the headbox, each individual of said plurality of metering devices including a metering channel having a metering channel opening and a metering channel center line, said metering channel opening being aligned such that said metering channel center line impinges on said turbulence generator to form an impingement point; a turbulence generator arranged immediately downstream of said intermediate channel in said flow direction of the at least one fibrous stock suspension has a plurality of flow channels arranged in a plurality of rows and columns; and a headbox nozzle arranged immediately downstream of said turbulence generator in said flow direction of the at least one fibrous stock suspension has a nozzle gap, said turbulence generator and said headbox nozzle being arranged in a second alignment plane, said first alignment plane and said second alignment plane forming an angle in a range of approximately between >90 and <180°. 